Comment by ampdepolymerase

You should try to convince the others on the Facebook groups to undergo full genome DNA sequencing (around $1K USD, usually not covered by insurance, I would pay for the other patients if I were you, their data is more than worth it given it’s your life on the line) and submit the data to patient networks and orphan drug groups. There are lots of bioinformatics methods now (thanks to mostly advances in ML among other things) that can derive insights into the problem, without any physical assays or laboratory tests.